TPS54308: High power consumption

Yan Pui Chan

Part Number: TPS54308
Other Parts Discussed in Thread: TPS54302

Hi,

I am using TPS54308DDCR in my design and found the power consumption is very high - 8.2mA with a 9V input and 3.3V output without any loads.

Do you have any ideas about what could go wrong?

Below is the schematic for your reference.

Notes:-

*Current was measured at FB1 (FB1 is removed)

**Removed R1 (no loads for testing purposes) still seeing high current draw.

***Removed R3 (Disabled TPS54308), the current is 0A.

Thanks

6 months ago

0 Gui He 6 months ago

TI__Mastermind 18916 points

Hi Yan

Can you please confirm that did you test the Iin with the IC disabled(R3 disconnedted) ? The converter doesn't switching and there is no output now ?

Thank you.

0 Yan Pui Chan 6 months ago in reply to Gui He

Intellectual 500 points

Hi Gui,

Yes, after R3 is removed (IC disabled), the output is 0V. The current is ~1.1uA at VIN.

I am wondering if the high power consumption is caused by the low efficiency when the output current is low?

Thanks.

0 Gui He 6 months ago in reply to Yan Pui Chan

TI__Mastermind 18916 points

Hi Yan

Is the - 8.2mA Iin tested with IC enabled(R3 not removed) and Io=0 ? That makes sense because TPS54308 is FCCM mode, which means it keeps in CCM mode under light load, and the efficiency under light load is relatively low because of the switching loss.

Thanks and best regards.

0 Yan Pui Chan 6 months ago in reply to Gui He

Intellectual 500 points

Hi Gui,

Do you have any pin-to-pin compatible DC to DC converter with better efficiency at light load?

This product has an option to be powered by the battery, so power consumption is critical.

Thanks.

+1 Gui He 6 months ago in reply to Yan Pui Chan

TI__Mastermind 18916 points

Hi Yan

TPS54302 is recommended.https://www.ti.com/product/TPS54302?keyMatch=TPS54302&tisearch=search-everything&usecase=GPN-ALT

Thanks and best regards.

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TPS54308: High power consumption